Originally Posted by
doggonecarl 
I see my co-workers at work. That's why they are called co-workers. When the whistle blows I go home.
It's nice that they ask you, but you don't have an obligation to go, except in you own mind.
I think it's also the industry I'm in. Finance is very work-hard/play-hard. (I hate that term, ugh) Lots of super high functioning alcoholics.
I've also worked in management consulting and many of them were cocaine addicts.